U.S. Pat. No. 3,880,302 the disclosure of which is incorporated herein by reference, describes a mechanism for the suspension and driving of a distribution chute of a charging installation of a shaft furnace. This mechanism has proved especially effective and advantageous, and since its creation it has equipped many charging installations of blast furnaces.
The replacement of the distribution chute, the inner lining of which has to be renewed regularly, can be carried out by means of a handling device of the type described in U.S. Pat. No. 4,729,549, the disclosure of which is incorporated herein by reference. According to this patent, the chute is extracted laterally through an orifice made in the upper conical part of the wall of the furnace. This does not present any problem, particularly as regards the new high-capacity furnaces which can be designed according to the particular type of charging installation. However, some problems can arise in the modernization of existing furnaces, especially blast furnaces of relatively low capacity in which the charging installation and the work platform are supported directly by the wall of the furnace. In this case, in fact, it is not possible to make an orifice in the furnace wall and in the work platform, to avoid reducing their stability and resistance, unless they have previously been reinforced by means of considerable and costly conversions.